The Moog 951 Keyboard is a single note CV keyboard with variable scale, range and portamento.
This keyboard has the earlier R. A. Moog logo.
The two calibrations are for range and scale when the front panel controls are set to 5. The jumper on the lower left is a factory option to be able to properly set the range trim.
The narrow portions of the plastic key contact strips in this Pratt-Read keyboard have warped so they are no longer straight and parallel. There is sufficient tolerance in the design so the keyboard still functions correctly.
As would be typical for a keyboard of this age, the bushings are rock hard. I replaced them with a new lubricated set from Vintage Vibe. I do the keyboard in small sections to not overly expose the fragile mechanism. It is real easy to displace out one of the return springs or lose a plastic cap.